Magnesium

The long-tailed character is called Magnesium (Mg) ( 人型Mg ), he also has a humanoid form.

Design
appears to be a Mechanize Parasite that look's like a Scorpion supporting Calne Ca

but in humanoid form he resembles kaito but it is not conform's on Deino's  Original Characters designs

Personality
doesn't conform that he has a personality According to deino he is Actually Calne Ca's Partner but it's still unknown that he has his own Personality

Biography
unknown

Voice configuration
Unknown

Relationships
Creatures that are frequently seen in videos accompanying Calne Ca are a walking skull called Chibi Cal-san (ちびカルさん), now officially known as Rubidium, it is the same kind of machine as Calcium, and doesn't have a mechanical body, though has been modeled by Deino to have a human figure in some of his images. Sometimes Calne will place a skin over the skull.[8]  The long-tailed character is called Magnesium (Mg) (人型Mg), he also has a humanoid form.[9] [10]

Calcium comics
by Deino3330 deviantART
 * Artwork
 * deviantArt Deino3330

Trivia

 * He is one of Deino's OC